Browsing by Subject "Micromechanics"

Now showing 1 - 3 of 3

Open Access
Computational homogenization of fatigue in additively manufactured microlattice structures
(Springer, 2023-02) Mozafari, Farzin; Temizer, İlker
A novel computational approach to predicting fatigue crack initiation life in additively manufactured microlattice structures is proposed based on a recently developed microplasticity-based constitutive theory. The key idea is to use the concept of (micro)plastic dissipation as the driving factor to model fatigue degradation in additively manufactured metallic microlattice. An ad-hoc curve-fitting procedure is proposed to calibrate the introduced material constitutive parameters efficiently. The well-calibrated model is employed to obtain fatigue life predictions for microlattices through a diverse set of RVE-based finite element fatigue simulations. The model’s predictive capabilities are verified by comparing the simulation results with experimental fatigue data reported in the literature. The overall approach constitutes a unified setting for fatigue life prediction of additively manufactured microlattice structures ranging from low- to high-cycle regimes. It is also shown that the model can be applied to technologically relevant microlattices with mathematically-created complex microstructure topologies.
Open Access
Smart composites with tunable stress-strain curves
(2018-12) Özcan, Müge
Smart composite materials with tunable stress-strain curves are examined numerically. Microscopic constituents of the composites respond to external stimuli by changing their elastic response in a well-defined, continuous and controllable manner, which defines the tunable traits of the macroscopic constituents. This inherently dynamic behavior of the constituents results in a display of characteristic properties that cannot be attained by any combination of traditional materials. A repetitive controller, which is intrinsically fits the types of applications desired for such composites where loading is cyclic, is used to prompt microscopic adaptation of the material. Stability and performance analysis are displayed in detail for the overall numerical framework over complex paths in macroscopic stress-strain domain. Later, the feasibility of designing and analyzing smart composites for real life applications are demonstrated by incorporating the control approach within a computational setting that is based on the finite element method on representative two- and three-dimensional tunable microstructures.
Open Access
Smart composites with tunable stress–strain curves
(Springer, 2020) Özcan, Mert; Çakmakçı, Melih; Temizer, İlker
Smart composites with tunable stress–strain curves are explored in a numerical setting. The macroscopic response of the composite is endowed with tunable characteristics through microscopic constituents which respond to external stimuli by varying their elastic response in a continuous and controllable manner. This dynamic constitutive behavior enables the composite to display characteristics that cannot be attained by any combination of traditional materials. Microscopic adaptation is driven through a repetitive controller which naturally suits the class of applications sought for such composites where loading is cyclic. Performance demonstrations are presented for the overall numerical framework over complex paths in macroscopic stress–strain space. Finally, representative two- and three-dimensional tunable microstructures are addressed by integrating the control approach within a computational environment that is based on the finite element method, thereby demonstrating the viability of designing and analyzing smart composites for realistic applications.